Drilling stem for drilling holes blown-out by pressurized air

ABSTRACT

A drilling stem which has a passage for drilling fluid, that is separated from a passage for pressurized air, and a chamber or tank for lubricant grease undergoing the pressure of the drilling fluid delivered from said separated passage, said tank being disposed above the drilling cutter bit. The drilling stem is also provided with means for charging the tank with lubricant grease and for draining the drilling fluid from the tank while the latter is being charged.

United States Patent 1 Kutuzov et al.

[451 July 31,1973

1 1 DRILLING STEM FOR DRILLING HOLES BLOWN-OUT BY PRESSURIZED AIR [76] Inventors: Boris Nikolaevich Kutuzov, Sirenevy bulvar, 43, kv. 42; Igor Grigorievich Mikheev, ulitsa P. Romanova, 15/58,

kv. 23; Vladimir Koustantinovich Grigoriev, Ljusinovskaya ulitsa, 53, kv. 53, all of Moscow; Vlktor Dmltrievich Chugunov, ulitsa Shkolnaya 4, kv. l3, Moskovskaya oblast, Solnechnogorsky raion, poselok Povarovo; Isaak Emmanullovich Narinlky, ulitsa Leningradskaya, 16, kv. 40, Khimki Moskovskoi oblasti; Alexandr Alexandrovlch Trusov, Konkovo-Derevlevo, Mikroraion 1, korpus 4, kv. 96; Georgy Ivanovich Sharonov, Samarkandsky bulvar, 34, korpus 3, kv. 66, both of Moscow; Viktor Fedorovich Golosov, sanatory imeni Artema, 2, kv. 43, Firsanovka Moskovskoi oblasti, all of U.S.S.R.

[22] Filed: July 3, 1972 [21] Appl. No.: 268,889

[52] US. Cl 175/228, 175/215, 173/74 [51] Int. Cl. E211) 21/00, E210 7/08 [58] Field of Search 175/227, 228, 229,

Primary Examiner-David H. Brown Attorney-John C. Holman and Marvin R. Stern [57] ABSTRACT A drilling stem which has a passage for drilling fluid, that is separated from a passage for pressurized air, and a chamber or tank for lubricant grease undergoing the pressure of the drilling fluid delivered from said separated passage, said tank being disposed above the drilling cutter bit. The drilling stem is also provided with means for charging the tank with lubricant grease and for draining the drilling fluid from the tank while the latter is being charged.

6 Claims, 9 Drawing Figures Patented July 31, 1973 3,749,186

6 Sheets-Sheet 1 Patented July 31, 1973 6 Sheets-Sheet 2 DRILLING STEM FOR DRILLING HOLES BLOWN-OUT BY PRESSURIZED AIR The present invention relates to hole drilling and, more particularly, to drilling stems used for drilling holes used preferably in quarries.

A drilling stern for drilling holes blown-out by pressurized air is known, which drilling stem comprises a rolling cutter bit connected to a pipe string having a passage separated from that for pressurized air and adapted to supply pressurized drilling fluid to dustsuppressing nozzles disposed above the bit.

During the operation of such a drilling stem the face of the hole remains dry, which makes the operating conditions of the rolling cutter bit better than in the case of dust-suppressing by way of supplying the drilling fluid to the hole face in the general flow of pressurized air, increases the rate of drilling and endurance of rolling cutter bits. At the same time, in this case dust is suppressed in a zone disposed behind the pipes and somewhat spaced from the hole face, i.e. in the hole zone that can be easily cleaned when drilling holes in quarries.

However, the conventional drilling stem does not provide for a substantial increase of the endurance of the rolling cutter bit and intensification of the drilling rates owing to an increase in the axial load acting on the bit and the rate of its rotation.

The above-mentioned disadvantages of the drilling stem decrease the effectiveness of its use.

It is an object of the present invention to provide such a drilling stem that, in the course of drilling holes by rolling cutter bits, would suppress dust by way of supplying drilling fluid into the zone disposed behind the pipes and spaced from the hole face and would effect, at the same time, lubricant greasing of the bearings of the rolling cutter bit supports in the case of employment of a tank for lubricant grease and possibility of controlling the lubricant grease consumption in the course of drilling.

The above-said and other objects are accomplished by that a drilling stem for drilling blown-out holes.

This task is accomplished by a drilling stem for drilling holes blown-out with pressurized air, comprising a rolling cutter bit connected with a pipe string having a passage separated from that for pressurized air and adapted to supply pressurized drilling fluid to dustsuppressing nozzles disposed above the bit, which drilling stem, according to the present invention, is provided with a chamber or tank disposed above the bit and adapted to contain lubricant grease pressurized by the drilling fluid delivered from said separated passage,

I means for charging the tank with the grease and draining the drilling fluid from the tank while the latter is being charged, and passages for supplying the grease from the tank to the bearings of the supports of the bit.

Owing to this embodiment of the drilling stem it is possible to effect a lubricant greasing of the bearings of the rolling cutter bit supports, which attributes to its endurance, to use the pressure of the drilling fluid supplied into the zone disposed behind the pipes in order to suppress dust for delivering the grease from the tank to the bearings of the bit supports, and to effect control over the grease consumption by varying the pressure of the drilling fluid.

It is expedient to make the means for charging the tank with grease as a spring-loaded slide valve disposed under the tank, and, during the charging operation, overlapping the passages connecting the tank with the bearings of the bit supports and opening the passage connected with the tank.

This simplifies and accelerates the process of charging of the tank with grease and does not require any special devices to be used for overlapping the passages communicating the tank with the bearings of the bit supports.

It is also expedient to make the means used for draining the drilling fluid from the tank as a non-return valve installed above the latter and communicated by a passage with the upper portion of the tank.

This preclude counter-pressure and contamination of the grease in the course of the charge of the tank with the grease, as well as prevents particles of products destroyed in the course of drilling from getting into the tank.

In order to provide for supply of grease into the bearings of the bit supports in the course of drilling, it is also expedient to mount in said separated passage two valves of which one is communicated with the dustsuppressing nozzles and opens an access to the latter. for the drilling fluid, and the other one is communicated by a passage with the tank containing the grease to let the drilling fluid get thereinto, the former valve being adjusted for a higher pressure than the latter one.

In order to use rationally the holding capacity of the tank with the lubricant grease, it is expedient to provide it with a scraping piston which separates the grease from the drilling fluid and moves as the level of the grease in the tank changes.

In order to increase the holding capacity of the tank with the lubricant grease, to make it possible to disposed the dust-suppressing nozzles at any point of the lower rod of the pipe string along the length of the tank and to simplify the design and technology of manufacture of the drilling stem at the point of disposition of the tank, itis expedient to make the lower rod of three coaxial pipes of which the central one forms a passage for the pressurized air, the central and inner ones con fine the tank for the grease, and the inner and outer ones form a separated passage for the drilling fluid supplied to the dust-suppressing nozzles.

The following description of an exemplary embodiment of the present invention is given with reference to the accompanying drawings, in which:

FIG. 1 schematically shows a drilling machine used for drilling holes blown-out with pressurized air by rolling cutter bits, having a drilling cutter stem mounted thereon and made in accordance with the present invention;

FIG. 2 shows the lower rod of the pipe string of the drilling stem with dust-suppressing nozzles and a tank for the lubricant grease supplied under the action of the pressure of the drilling fluid to the bearings of the bit supports, a longitudinal section;

FIG. 2' is ditto;

FIG. 3 shows a dust-suppressing nozzle used for delivering the drilling fluid into the hole zone disposed behind the pipes (unit A" in FIG. 2), a longitudinal section;

FIG. 4 shows a spring-loaded slide valve used for charging the tank with the grease and a throttle used for controlling the grease consumption (unit B" in FIG. 2), a longitudinal section;

FIG. 5 is a section taken along line V-V of FIG. 4;

larged portion 29 carried adjacent the other end which abuts against the bracket so that when a locking nut 30 is threaded on the end of shaft 28 and drawn tightly against the bracket, the shaft is firmly secured to the bracket. It is to be understood, of course, that there are many ways for suitably securing shafts 25 and 28 to the bracket.

The loom beam C is carried on a conventional shaft 31 which is, in turn, supported between a pair of conventional standards 32 having a bifurcated portion 33 adjacent the top thereof. The beam has a conventional beam gear 34 secured thereto, which rotates with the beam.

The means, generally designated by the reference character B, coupling shaft A in driving relation to the storage roll, or beam C, includes a pinion gear 35 which meshes with the beam gear 34. The pinion gear 35 is attached to a shaft 36 which has a worm wheel 37 fixed to the other end. Shaft 36 is supported on a bearing for free rotation in a bracket 38 which is shown in more detail in FIG. 1A. Slots 39 are provided in the lower portion of the bracket to accommodate bolts to attach the bracket to the side of the loom frame. The bracket 38 has a pair of outwardly extending shoulders 40 and 41 through which the shaft 36 passes. The shoulder 41 terminates in a reduced diameter portion 42 which has a needle bearing 43 in the end thereof.

A supporting plate 44 having a pair of opposed collars 44a and 44b (see FIG. 1B) is provided for supporting other mechanism described below. inwardly extending collar 44a is placed on the reduced portion 42 of the bracket 38 and is secured thereto by a set-screw 44c. The shaft 36 extends through the shoulders 40 and 41 and has the worm wheel 37 secured on the outer end thereof for fixed rotation therewith. The supporting bracket has two pairs of supporting arms 45 and 46 carried adjacent the top and bottom thereof and extending outwardly therefrom. Shaft A extends through the aligned holes 47 in the supporting arms 46 and has the braking member D secured on one end thereof. A worm 48 is carried on the shaft A, and is fixed thereto by any suitable means, such as keying, and is carried in mesh with the worm wheel 37 so that the shaft A, shaft 36, and the beam gear 34 are directly coupled together for rotation in unison. A hand crank 49 is attached to the other end of a shaft A so that the shaft can be rotated by hand when it is desired to disengage the braking mechanism in order that the storage roll C can be rotated relatively freely. The lead angle of the worm 48 and the worm wheel 37, which form a worm gear, is sufficient to allow the worm wheel 37 to drive the worm 48 and shaft A thus turning the braking member D.

The braking means D includes a circular pulley having a flat braking surface 70. The member E which aids in manipulating the band F which extends around the braking member D includes an elongated arm 50. The end of the arm 50 is fixed to a shaft 51 which extends between holes 52 carried adjacent the outer end of the supporting arms 45. The shaft 511 is journalled on bearings (not shown) so that it can rotate freely in the arms 45. A lever arm 53 is fixed to the other end of the shaft 51 which extends beyond the supporting arms 45 and extends inwardly toward the loom beam. By raising and lowering the lever arm 53, the arm 50 will pivot accordingly.

Positioned on the pivotal arm 50 are inner post 54 and outer post 55. These posts are spaced radially from the center of the circular braking member D.

The band F has one end looped around the outer post 55 and extends around the braking surface between the inner post 54 and the outer post and upwardly back around the outer post 55, with the ends joined by clamping member 56. The clamping member 56 extends thorugh both ends and a portion of the band leading toward the braking member D so as to anchor the band relative to member E. The inner post 54 of the band bears against an outer surface of the band so that by pivoting the arm 50 the frictional contact between the band F and the drum can be varied to regulate the braking effect.

The means G for sensing the tension in the yarns 10 includes the tension sensing roller 12 which moves to and from the loom beam responsive to variations in tension in the yarn extending around the roller 12. A yoke 57 (FIG. 3) having a bifurcated and extends over the reduced end of shaft 18 upon which the tension roller 12 is carried and is attached thereto by a pin 58 extending between the ends of the yoke 57. The other end of the yoke 57 has a bore extending therethrough, through which a flexible cable 59 passes. A collar 61 is attached to the inner end of the cable 59'by a set-screw and a compression spring 63, which acts as a shock absorber to minimize the jerking motion produced as the yarn is beat up during the weaving operation, is positioned between collar 61 and the inner end of the yoke. Other mechanical means may also, of course, be used to secure cable 59 to the yoke 57, if desired. The flexible metal cable 59 extends upwardly adjacent the standard 32 and has its other end attached to the lever arm 53. The cable 59 passes through a hole in the lever arm 53 and is secured thereto by an enlarged collar fixed on the end thereof on the underside of arm 53 so that when the tension roller 12 moves towards the loom beam, tension will be applied to the cable and lever arm 53 will be raised. When roller 12 moves away from the loom beam, slack is formed in cable 59, whereby lever arm 53 pivots downwardly, causing arm 50 to pivot counterclockwise and create tension on band F and the circular pulley. The increased frictional contact between the band F and the pulley, of course, in turn will decrease the speed of rotation of the loom beam. The cable is supported by a bracket 65 carried on the bracket 15. Another bracket 64 carried by standard 32 positions the cable 59 directly above the lever arm 53. The cable is a conventional cable, such as a speedometer cable, and is enclosed within a flexible tubular member 66 to allow the cable to move freely in response to movement of the tension roller 12.

In operation, as the yarns are drawn off of the loom beam C they pass around the tension roller 12 prior to being fed into the weaving mechanism of the loom. The tension roller 12 exerts the desired tension on the warp yarn which can be varied by adding or removing weights 23 off of the chain 21. The tension in the warp yarn 10 causes a turning effect on the loom beam C. As the loom beam C turns, the beam gear 34, which meshes with the pinion gear 35, rotates and causes shaft 36 and the worm wheel 37 to rotate. Rotation of the worm wheel 37, in turn, causes the shaft A upon which the braking member D is carried to turn when not otherwise restricted by the frictional contact between the band F and its flat surface 70.

wall 53 of the sleeve 39. The nut has a plurality of through holes 54 through which the drilling fluid passes.

Thus, within the nipple 30 the passage 16 for the pressurized air is confined by an internal space 55 of the sleeve 39 and an internal space 56 of the sleeve 40, whereas the passage 24 for the drilling fluid, which is separated from the passage 16, is confined by the holes 54 made in the nut 50, an annular gap 57 between the nipple 30 and the sleeve 39, the longitudinal slots 47 made in the head 45 of the sleeve 40, which are confinedby the internal wall 46 of the nipple 30, and an annular gap 58 between the nipple 30 and the sleeve 40.

The hermetic sealing of the passage 16 for the pressurized air and the passage 24 for the drilling fluid, which is separated from the passage 16 is ensured at the points of joints 59 (FIG. 1) of the rods 8 of the pipe string 7 owing to packing along the taper thread 31 between these rods 8 and a butt-end packing along the butt-end 60 of the sleeve 39 mounted in the nipple 30 of these rods 8 so that it can displace over a limited distance. Elimination of possible gaps along the butt-end 60 (FIG. 2) of the sleeve 39 and guaranteed pressing of the butt-end 60 the sleeve 39 against the butt-end of the subsequent rod 812 are effected owing to resilient properties of the packing ring 49 made from a resilient material, such as oil-resistant resin.

Along the length of the main pipe 33 of the lower rod 8a of the pipe string 7 the passage 16 for pressurized air is confined by an internal space 61 of a central pipe 62 whose upper end passes loosely through the adapter 32 and lower one is rigidly connected by means of a threaded joint 63 with the coupling 34 used to connect the pipe string 7 with the bit 6. In order to hermetically seal the threaded joint 63, a packing 64 is disposed between the central pipe 62 and the coupling 34, while the central pipe 62 is sealed at the side of the adapter 32 with the aid of packing rings 65a and 65b mounted in an internal wall 66 of the sleeve 42 and packing rings 65c and 65d mounted in an internal wall 67 of the adapter 32. The passage 16 for pressurized air terminates in an internal central passage of the coupling 34 of the lower rod 8a of the pipe string 7, whereafter the pressurized air is delivered into the rolling cutter bit 6.

In the adapter 32 the passage 24 for drilling fluid, which is separated from the passage 16 for pressurized air, is divided into two parts, as a result of which a part of the drilling fluid is supplied to the dust-suppressing nozzles 19 and the other part to the tank 25 containing lubricant grease.

The drilling fluid is supplied to the dust-suppressing nozzles 19 through longitudinal slots 69 made in an external wall 70 of the sleeve 42, confined by an internal wall 71 of the adapter 32, via an annular boring 72 in the external wall 70 of the sleeve 42, radial openings 73 of the sleeve, an internal annular boring 74 made in the internal wall 66 of the sleeve, an annular gap 75 between the central pipe 62 and the adapter 32, a nonreturn valve 76 mounted in the adapter 32, an annular boring 77 and a longitudinal passage 78 communicated with the latter and made in the adapter 32, an annular space 79 confined by the adapter 32, the main pipe 33 and a sleeve 80, and, finally, via an annular gap 81 between the main pipe 33 and an internal pipe 82 forming the external wall of the annular tank 25 containing lubricant grease, and by the sleeve serving as the cover of the annular tank 25 containing the lubricant grease.

The dust-suppressing nozzles 19 (F168. 2 and 3) are secured in the main pipe 33 of the lower rod 8 a of the pipe string 7 by means ofa taper threaded joint 83, and, in order to simplify their replacement, have a shaped, for example, a hexahedral opening 84 fitting a wrench. In order to preciude the dust-suppressing nozzles 19 and taper threaded joints 83 against abrasive wear, they are sunk in the main pipe 33 and do not protrude be yond its diameter, which is ensured by the fact that the taper threaded joint 83 is disposed in borings 85 made in the external wall 86 of the main pipe 33 and having a diameter which is greater than that of the taper threaded joint 83.

The drilling fluid delivered into the annular gap 81 between the main pipe 33 and the internal pipe 82 is further supplied into the zone 18 (FIG. 1) disposed behind the pipes through openings 87 (FIG. 3) made in an internal wall 88 of the main pipe 33, spaces 89 confined by the openings 87 and the dust-suppressing nozzles 19, a calibrated opening 90 made in the nozzles and borings 85 made in the external walls 86 of the main pipe 33 of the lower rod 8a of the pipe string 7. The inner diameter of the calibrated openings 90 made in the dust-suppressing nozzles 19, the number of the dust-suppressing nozzles and their disposition in the main pipe 33 of the lower rod 80 depend on the conditions of drilling.

The annular tank 25 containing lubricant grease is disposed in the main pipe 33 of the lower rod 80 of the pipe string 7, and is limited with respect to its height by an upper butt-end 91 of the coupling 34 and a lower butt-end 92 of the adapter 32, and with respect to its side walls by the central pipe 62 and the internal pipe 82. The upper portion of the tank 25 containing lubricant grease, disposed between the internal pipe 82 and an annular projection 93 of the adapter 32 is closed by the sleeve 80. In order to hermetically seal a sliding joint 94, a packing ring 95 is mounted between the sleeve 80 and the annular projection 93, and in order to hermetically seal a sliding joint 96, a packing ring 97 is mounted between the sleeve 80 and the internal pipe 82. In order to limit the displacement of the sleeve 80 and to provide for a free passage of the drilling fluid from the longitudinal passage 78 made in the adapter 32 into the annular space 79, a check ring is mounted in the annular space 79 between the upper butt-end 98 of the sleeve 80 and the annular recess 99 of the adapter 32. In order to isolate the lower portion of the tank 25 containing lubricant grease from the annular gap 81 used for supplying the drilling fluid to the dust-suppressing nozzles 19, a sleeve 102 having an annular projection 103 adjoining a respective boring 104 made in the internal wall 88 of the main pipe 33 is rigidly connected to the lower end portion of the internal pipe 82 by means, for example, a weld joint 101. lnserted into the sleeve 102 is an additional sleeve 105 having an annular projection 106 adjoining the upper butt-end 91 of the coupling 34. Disposed between the annular projection 103 of the sleeve 102 and an annular projection 106 of the additional sleeve 105 is a packing ring 107 made from a resilient material. With the coupling 34 connected by means of the taper thread 38 with the main pipe 33, the butt-end 91 of the coupling 34 presses on the annular projection 106 of the additional sleeve 105 and compresses the packing ring 1117, thereby reliably isolating the lower portion of the tank containing lubricant grease from the annular gap 81 used for supplying the drilling fluid to the dust-suppressing nozzles 19.

Thus, at the point of disposition of the annular tank 25 containing lubricant grease the rod 8a (FIG. 2) is made from three coaxial pipes of which the central pipe 62 has the internal space 61 forming a part of the passage 16 for pressurized air, the central pipe 62 and the internal pipe 82 form an annular tank 25 containing lubricant grease, and the internal pipe 82 and the external (main) pipe 33 form a part of the passage 24 for drilling fluid supplied under pressure to the dustsuppressing nozzles 19. This embodiment of the rod 8a makes it possible to increase the holding capacity of the annular tank 25 containing lubricant grease, owing to the possibility of making it aimost along the whole length of the rod 8a, and to dispose the dustsuppressing nozzles 19 at any point of the rod within the limits of the length (height) of the annular tank 25 containing lubricant grease. Besides, this considerably simplifies the design and technology of manufacture of the drilling stem 1.

The part of the drilling fluid delivered into the annular tank 25 containing lubricant grease is supplied thereinto from the annular gap 58 between the nipple and the sleeve via a passage 108 made in the adapter 32, an annular boring 109 made in a body 110 of a means 111 for draining the drilling fluid from the annular tank 25 while it is being charged with lubricant grease, a passage 112 which is essentially a continuation of the passage 108, a non-return valve 113, a passage 114 closed at the side of the annular recess 99 of the adapter 32 by a plug 115, a passage 116 communicated with the passage 114 and closed by a plug 117, and, finally, via a passage 118 communicated with the passage 116 and entering the annular tank 25 at point of the lower butt-end 92 of the adapter 32.

Disposed under the annular tank 25 containing lubricant grease in the coupling 34 is a means 119 (FIGS. 2 and 4) used for charging the annular tank 25 with lubricant grease. This means 119 is fashioned as a spring 120 loaded slide valve 121 which, in the course of charging, overlaps a passage 122 which is essentially a part of the passage used for supplying the lubricant grease from the tank 25 to the bearings 25, 27 and 28 (FIG. 6) of the supports 29 of the rolling cutter bit 6, and opens a passage 123 connected with the tank 25. The slide valve 121 is mounted in the cylindrical space 124 of the coupling 34 and has the shape of a cylindrical sleeve, whereas the spring 120 thrusts by its one end against a bottom 125 of the cylindrical sleeve (slide valve) 121, and by its other end against a bottom 126 of the cylindrical space 124. In order to preclude the slide valve 121 from falling out of the cylindrical space 124 of the coupling 34 in the course of charging of the tank 25 with lubricant grease, use is made of a nut 127 having a threaded joint 128 with the coupling 34. The nut 127 is provided with a central through opening 129 accommodating the charging pipe union of the device (not shown in the drawing) used for charging the tank 25 with lubricant grease, which may be of any appropriate design. This central through opening 129 is made, at the same time, shaped, for instance, hexahedral and fits a wrench used for screwing in or out the nut 127. It is expedient to mount a packing 130 between the slide valve 121 and the nut 127. In

order to preclude contamination of the means 119 for charging the annular tank 25 with lubricant grease in the course of drilling, it is closed with a plug 131 having a threaded joint 132 with the coupling 34 and a dead opening 133 fitting the wrench and having the same shape as the central through opening 129 of the nut 127. In order to preclude its falling out of the coupling 34, the plug 131 is fixed by means of a spring ring 134 inserted into an annular boring 135 of an opening 136 of the coupling 34, a packing ring 137 being used to hermetically seal the threaded joint 132 of the plug 131 with the coupling 34. In order to make it easier to extract the slide valve 121 from the cylindrical space 124 of the coupling 34 in the case of its wedging, the slide valve 121 has a dead opening 138 having a threading 139.

Mounted in the coupling 34 below the means 119 is a throttle 140 (FIGS. 1, 4 and 5) used for controlling the consumption of grease. The throttle 140 is mounted in a cylindrical space 141 of the coupling 34 and has an adjusting head 142 whose diameter is smaller than that of the cylindrical space 141, a packing ring 143 and a threaded head 144 used to secure the throttle 140 in the coupling 32 and having a slot 145 fitting a screwdriver. In order to fix the throttle 140 in the coupling 34, use is made ofa locknut 146 having a threaded joint 147 with the coupling 34 and a central through opening 148 fitting a wrench of preferably the same shape and size as the openings 129 and 133. The locknut 146 and the throttle 140 are precluded against falling out of the coupling 34 by means of a spring ring 149 which is inserted into an annular boring 150 of an opening 151 of the coupling 34. With the throttle 140 rotated by a screw-driver inserted into the slot 145, the adjusting head 142 of the throttle 140 changes the crosssectional area of an opening 152 intercommunicating the passage 122 and the cylindrical space 141, thereby controlling the delivery of the lubricant grease into the cylindrical space 141 and, consequently, to the bearings 26, 27 and 28 of the supports 29 of the rolling cutter bit 6 (FIG. 6).

From the cylindrical space 141 the lubricant grease is delivered into passages 153 and 154 which are disposed horizontally, are bored in the coupling 34 and are closed by plugs 155 and 156 at the side of the zone 18 disposed behind the pipes, the plugs 155 and 156 being secured to the coupling 34 by weld joints 157 and 158 (FIG. 5).

From the passage 154 the lubricant grease is supplied into a vertical passage 159 bored at the side of a buttend of the coupling 34. The outlet of the vertical passage 159 is closed at the butt-end 160 of the coupling 34 by a plug 161. From the vertical passage 159 the lubricant grease is delivered further into a horizontal passage 162 bored in the coupling 34 and closed at the side of the zone 18 disposed behind the pipes by a plug 163. From the horizontal passage 162 the lubricant grease is delivered into an annular boring 164 provided on the internal taper thread 35 of the coupling 34. From the annular boring 164 the lubricant grease gets through radial openings 165 made in a nipple 166 of the rolling cutter bit 6 into an annular space 167 disposed inside the nipple 166 and confined by a central pipe 168 of the rolling cutter bit and a cover 169 which is rigidly connected, for instance, by means of weld joints 170 and 171 with the central pipe 168 and a buttend 172 of the nipple 166 of the rolling cutter bit 6.

From the annular space 167 the lubricant grease is delivered into a passage 173 provided in each flange 174 of the rolling cutter bit 6, wherefrom the lubricant grease gets via an annular space 175 confined by an annular boring 176 in a locking pin 177 and walls 178 of cylindrical opening fitting the locking pin 177 into a passage 179 made in a journal 180 of the rolling cutter bit 6. From the passage 179 provided in the journal 180 the lubricant grease is supplied into the support 29 of the rolling cutter bit 6 and lubricates the support 29, thereby improving the operating conditions of the bear ings 26, 27 and 28. It is possible to use as the bearings in the support antifriction bearings made, as is shown in FIG. 6, according to the roller-ball-roller diagram or any other one, as well as sliding bearings or combined ones. The used-up lubricant grease is pushed out into the zone 18 disposed behind the pipes through an annular gap 181 between a tail portion 182 of the rolling cutter bit 183 and the flange 174. In addition to improvement of the operating conditions of the bearings 26, 27 and 28 of the supports 29, the lubricant grease prevents particles of destruction products into the supports 29, which additionally increases the endurance of the supports and, consequently, the rolling cutter bit 6 as whole. The bit 6 shown in FIG. 6 consists of three cutters, and only one left-hand flange 174 is shown in section, whereas one flange 174 is extracted for illustration purposes, the designs of all the flanges and the supports 29 being similar.

When drilling watered rock, the bit 6 may be provided with a non-return valve 184 mounted inside thereof and protecting the inner space (separated passage 16) of the drilling stem against penetration of a mixture of water and particles of destruction products, said valve 184 being of any appropriate design. As is shown in FIG. 6, the non-return valve 184 has a body 185 having the shape of a cylindrical sleeve, and being provided with a threaded joint 186 with a central pipe 168 and an opening 187 for passage of pressurized air, the opening 187 inner edge 188 being essentially a valve seat. The valve proper is fashioned as a ball 189 whose diameter is smaller than the diameter of the body 185 of the valve 184 and greater than the diameter of the opening 187 for passage of pressurized air. The ball 189 is pressed against the edge 188 of the opening 187 by a spring 190 which thrusts against a washer 191 disposed between the body 185 and the central pipe 168 and having an opening 192 for passage of pressurized air into an internal space 193 of the central pipe 168, and, then, further, to the face 17 of the hole 9 (FIG. 1) being drilled. During the operation of the compressor 13 the pressurized air presses aside the ball 189 and passes freely to the face 17 of the hole 9, whereas in the ease of stoppage of the compressor, for example, during lowering or hoisting operations, or when the electric energy supply is discontinued in the case of emergency, the spring 190 presses this ball 189 against the edge 188 of the opening, as a result of which water and particles of destroyed products cannot penetrate inside the drilling stem.

. Since during the charging of the annular tank 25 with lubricant grease, the latter is filled with the drilling fluid which is essentially a non-compressible liquid, the tank 25 must be provided with a means 111 (FIG. 2) used for draining the drilling fluid in the course of charging. This means is fashioned as a non-return valve (FIG. 7) mounted above the tank 25 in the adapter 32 and connected by means of a passage 194 communicated with the passage 118 with the upper portion of the tank 25. The non-return valve shown in FIG. 7 consists of a body made as a cylindrical sleeve and having a taper seat 195, and a valve 196 proper, made as a rod with a locking member 197 of a greater diameter, which has a reverse taper portion 198 contacting, when the valve is closed, the taper seat in the body 110. The taper portion 198 of the locking member 197 of the valve 196 is pressed against the taper seat 195 of the body 110 by a spring 199 disposed between a bottom 200 of the body of the valve 110 and a nut 201 screwed onto a threaded tail 202 of the valve 196. The body 110 of the non-return valve 111 is disposed in a cylindrical space 203 of the adapter 32 and thrusts against an annular projection 204 of the adapter to which it is pressed by a nut 205 having a threaded joint 206 with the adapter 32, and a central opening 207 for draining the drilling fluid from the annular tank 25 while it is being charged with lubricant grease. The nut 205 is precluded from falling out of the adapter 32 by a spring ring 208 inserted into an annular boring 209 made in the adapter 32, and has a slot 210 fitting a screw-driver. The body 110 of the non-return valve 111 is packed in the adapter 32 by means of two packing rings 211a and 211b disposed at both sides of the annular boring 109 made in the body 110 of the non-return valve 111.

As it has already been said above, in the adapter 32 (FIG. 2) the passage 24 for drilling fluid, which is separated from the passage 16 for pressurized air, is divided into two parts, as a result of which a part of the drilling fluid is supplied to the dust-suppressing nozzles, and the other part is supplied into the tank 25 containing lubricant grease. For this purpose, the separated passage 24 for drilling fluid has two non-return valves 76 and 113 mounted therein, of which valves one (76) is connected by the passage 78, the annular space 79 and the annular gap 81 with the dust-suppressing nozzles 19 and makes an access to the latter for the drilling fluid supplied under pressure, and the other one (113) is connected by the passages 114, 116 and 118 with the tank 25 containing lubricant grease, the first valve 76 being adjusted for a higher pressure than the second valve 113. This makes it possible to supply lubricant grease to the bearings 26, 27 and 28 of the supports 29 of the rolling cutter stem 6 in the course of drilling without simultaneous supply of the drilling fluid to the dust-suppressing nozzles 19. At this moment dust may be suppressed by way of supplying the drilling fluid to the face 17 of the hole in a general flow of pressurized air with the aid of conventional means.

A hollow cylindrical body 212 (FIG. 8) of the nonreturn valve 76 is mounted in a cylindrical space 213 of the adapter 32 and thrusts against an annular projection 214 of the adapter to which it is pressed by a nut 215 having a threaded joint 216 with the adapter 32 and a central entered by a cylindrical tail 217 of the cylindrical body 212 of the non-return valve 76. In order to screw the nut 215 in or out of the adapter 32, use is made dead openings 218a and 218k disposed in diametral opposition, and a spring ring 219 inserted into an annular boring 220 made in the adapter 32 prevents the nut from withdrawal from the adapter 32. The cylindrical body 212 of the non-return valve 76 is packed in the adapter 32 by a packing ring 221 mounted in an annular boring 222 of the body 212, whereas, in order to make it easier to extract the body 212 from the cylindrical space 213 of the adapter 32, provision is made for a dead opening 223 with a threading 224, disposed in the cylindrical tail 217 of the body 212. A seat 225 of the non-return valve 76 is fashioned as a nut having a threaded joint 226 with the body 212 of the valve, a central opening 227 for passage of the drilling fluid and a slot 228 fitting a screw-driver. The valve proper is made as a ball 229 whose diameter is smaller than that of an internal space 230 of the body 212 and is greater than that of the central opening 227 of theseat 225. The ball 230 is pressed against the central opening 227 of the seat 225 by a spring 231 which thrusts against a bottom 232 of the internal space 230 of the body 212. The central opening 227 of the seat 225 is communicated with the annular gap 75 through a radial opening 233, and the internal space 230 of the body 212 is communicated with the longitudinal passage 78 made in the adapter 32 through a radial opening 234 and the annular boring 77 in the body 212. In the course of drilling the drilling fluid presses aside the ball 229 and opens an access for the dust-suppressing nozzles 19. When the pressure of the drilling fluid drops, for instance, in the case of drilling-in or discontinuation of its supply, a spring 231 presses the ball 229 against the opening 227, thereby overlapping the separated passage 24.

The body of the non-return valve 113 (FIG. 7), which opens an access for the drilling fluid to the tank 25 containing lubricant grease, is made as a sleeve 235 mounted in a cylindrical space 236 of the adapter 32 and thrusting against its bottom 237 to which it is pressed with the aid of a packing washer 238 and a nut 239. The packing washer 238 has a packing ring 240 mounted in its outer annular boring, and a dead opening 242 with a threading 243 to make it easier to extract it from a cylindrical space 236 of the adapter 32. The nut 239 has a threaded joint 244 with the adapter 32 and a central through shaped opening 245 fitting a wrench of the same shape as that for the lug 131 and the locknut 146, a spring ring 246 being inserted into an annular boring 247 of the adapter 32 to preclude the withdrawal of the nut 239 from the adapter 32. The valve proper is made as a cylindrical slide valve 248 disposed in an internal space 249 of a sleeve 235, which, when closed (as is shown in FIG. 7), is pressed against the packing washer 238 by a spring 250 which by its one end thrusts against the bottom 237 of the cylindrical space 236 of the adapter 32 and by its other end against a bottom 251 of a cylindrical space 252 in the cylindrical slide valve 248. The cylindrical slide valve 248 has a tail of a smaller diameter, in which a dead opening 254 with a threading 255 is made to make it easier to withdraw it from the internal space 249 of the sleeve 235. In the course of drilling the drilling fluid supplied to the non-return valve 113 from the passage 112 made in the adapter 32, passes into an annular boring 256 of the sleeve 235, and, then, through slots 257 of the sleeve 235 into an annular space 258 confined by the tail 253 of the cylindrical slide valve 248 in the internal space 249 of the sleeve 235. Thereby, the drilling fluid presses upon the cylindrical slide valve 248 which, while compressing the spring 250, moves to the right until it thrusts against the bottom 237 of the cylindrical space 236 of the adapter 32 and opens radial passages 259 extending into an annular boring 260 made in the sleeve 235 which is communicated with the pas sage 114 connected, as it has been said afore, with the tank 25 containing lubricant grease. Concurrently, the

cylindrical slide valve 248 overlaps radial passages 261 and 262 extending into external cuts 263 and 264, respectively, of the sleeve 235, of which the former is communicated with the passage 194 in the adapter 32 and the latter with the passage 118 made in the same adapter 32. This overlaps the access of the drilling fluid to the means 111 used for draining the drilling fluid from the tank 25 containing lubricant grease. While the tank 25 containing lubricant grease is being charged, no drilling fluid is supplied, and, therefore, the spring 250 presses the cylindrical slidevalve 248 to the left, thereby overlapping the radial passages 259 communicated, as it has been noted afore, with the separated passage 24 for drilling fluid, and opening the radial passages 261 and 2 62 communicated with the means 111 used for draining drilling fluid from the tank 25 containing lubricant grease.

In order to use rationally the holding capacity of the annular tank 25 containing lubricant grease, the latter accommodates a scraping piston 265 (FIG. 2) which separates the lubricant from the drilling fluid and moves as the level of the lubricant grease in the tank 25 changes. The scraping piston 265 comprises a sleeve 266 sliding along the central pipe 62 and having a flange 267 with openings 268, a ring 270 made from an elastic material, such as rigid oil-resistant rubber or nylon, sliding along the internal wall 269 of the inner pipe 82 and having openings 271, and a ring 272 having openings 273. The ring 270 is pressed inbetween the flange 267 of the sleeve 266 and the ring 272 by bolts 274 entering the openings 268, 271 and 273 and nuts 275 whose self-unscrewing is precluded with the aid of split spring washers 276. When in its upper position, the scraping piston 265 thrusts byits ring 272 against the sleeve 80, thereby protecting the ring 270 made from an elastic material against damage. The scraping piston 265 attributes to a better transmission of the pressure of the drilling fluid, and, as it moves downwards, it scrapes a layer of lubricant grease off the walls 269 and 277 of the inner pipe 82 and the central pipe 62, which has adhered thereto.

The drilling stem functions as follows.

The machine is brought to a point at which the hole 9 (FIG. 1) is to be drilled, is set into its operating position with the aid of the horizontal hydraulic jacks 4, whereupon drilling of the hole 9 is started. In order to effect this, the pumping unit 20, the compressor 13, the rotating device 11 and the feeding device 10 are successively started.

Thereby, the drilling fluid is delivered from the tank 21 along the pipe-line 22 into the pumping unit 20, and farther along the hose 23 into the swivel 15. The swivel 15 is adapted to supply the drilling fluid both into the passage 24 for drilling fluid, which is separated from the passage 16 (FIG. 2) for pressurized air, and into the both passages 16 and 24. During drilling-in the drilling fluid is delivered simultaneously into the both passages 16 and 24.

The drilling fluid 24 getting into the passage 24 passes through the swivel 15, the rods 8, which are disposed above, and the openings 54 made in the rod 8a (FIG. 2), and, then, into the annular gap 57, the slots 47 made in the-head 45 of the sleeve 40 and confined by the internal wall 46 of the nipple 30, the annular gap 58, the passage 108 made in the-adapter 32, the annular boring 109 in the body 110, confined by the body of the adapter 32 and into the passage 112. From the passage 112 the drilling fluid is delivered to the nonreturn valve 113 in which it gets into the annular boring 256 (FIG. 7), the slots 257, the annular space 258 to displace the cylindrical slide valve 248 of the nonreturn valve 113 to the right, thereby opening the radial passages 259, enters the latter, then the annular boring 260, the passage 114, the passage 116 (FIG. 2), and, finally, through the passage 118 is delivered into the annular tank 25 containing lubricant grease. Simultaneously, while moving to the right, the cylindrical slide valve 248 overlaps the radial passages 26] and 262, thereby discontinuing the supply of the drilling fluid to the means 111 used for draining the drilling fluid. At the same time, from the annular gap 58 the drilling fluid is supplied into the longitudinal slots 69 provided on the external wall 70 of the sleeve 42, confined by the internal wall 71 of the adapter 32, the annular boring 72, the radial openings 73, the internal annular boring 74, the annular gap 75, the radial opening 233 (FIG. 8) and, finally, into the central opening 227 of the seat 225 of the non-return valve 76. However, the drilling fluid is not supplied to the dust-suppressing nozzles 19 (FIGS. 1 and 2.), as in the case of drilling-in the pressure of the drilling fluid is maintained to be lower than the one required for opening the non-return valve 76.

The drilling fluid delivered into the tank 25 containing lubricant grease presses the scraping piston 265 which separates the lubricant grease from the drilling fluid, and the lubricant grease is delivered through the passage 122 (FIG. 2) in the coupling 34, the opening 152 (FIGS. 4 and 5), the cylindrical space 141, horizontally disposed passages 153 and 154 (FIG. 5), the vertical passage 159 (FIG..6), the horizontal passage 162, the annular boring 164 confined by the nipple 166 of the rolling cutter bit 6, the radial openings 165 made in the nipple 166, the annular space 167 provided in each flange 174 of the rolling cutter bit 6, the passages 173, the annular space 175, and, finally, the passage 179 made in the journal 180 into the supports 29 of the rolling cutter bit 6 to lubricate them and, consequently, to improve the operating conditions of the bearings 26, 27 and 28. The used-up lubricant grease is pushed out into the zone 18 (FIG. 1) disposed behind the pipes through the annular gap 181 (FIG.6) to prevent particles of destroyed products from getting into the supports, thereby increasing the endurance of the latter and, consequently, of the rolling cutter bit 6 as a whole.

The control over the lubricant grease consumption is effected in the course of drilling by varying the pressure of the drilling fluid: with the pressure raised, the consumption of the lubricant grease increases, and with the pressure dropped, the consumption of the lubricant grease decreases. In order to vary the pressure of the drilling fluid, it is necessary to change respectively the output of the pumping unit 20.

The preliminary control over the consumption of the lubricant grease is effected with the aid of the throttle 140 (FIGS. 4 and 5) by changing the cross-sectional area of the opening 152, for which purpose a screwdriver is inserted into the slot 145 of the threaded head 144 of the throttle 140, and, in order to decrease the consumption of the lubricant grease the throttle 140 is screwed into the coupling 34, and, in order to raise the consumption of the lubricant grease, it is screwed out. Thereby, the adjusting head 142 of the throttle 140 respectively decreases or increases the cross-sectional area of the opening 152. The required position of the throttle 140 is fixed by the locknut 146.

The drilling fluid that is delivered in the course of drilling-in into the passage 16 (FIG. 2) for pressurized air is mixed with the latter, and is delivered together therewith through the swivel l5 and the rods 8 which are disposed above into the internal space J55 of the sleeve 39 and farther into the internal space of the sleeve 40, the internal space 61 of the central pipe 62 and the inner central passage 68 of the coupling 34. Then, the mixture of the drilling fluid and air is delivered to the non-return valve 184 (FIG. 6), presses aside the ball 189, passes through the opening 187 and the opening 192, and, finally, through the internal space 193 of the central pipe 168 is supplied to the face 17 of the hole 9 to clean the latter and, at the same time, to suppress dust in the face 17.

With the dust-suppressing nozzles 19 (FIG, 1) entered the hole, the supply of the drilling fluid into the passage 16 (FIG. 2) for pressurized air isdiscontinued, as a result of which the pressure of the drilling fluid raises to become sufficient to open the non-return valve 76. The ball 229 (FIG. 8) movesto the right, thereby compressing the spring 231, and the drilling fluid passes from the central opening 227into the internal space 230 of the body 212 of the non-return valve 76 and farther through the radial openings and the annular boring 77 into the longitudinal passage 78 made in the adapter 32 (FIG. 2), the annular space 79 and the annular gap 81. From the annular gap 81 the drilling fluid is delivered through the openings 87 (FIG. 3) in the main pipe 33 and spaces 89 to the dustsuppressing nozzles 19, passes through the calibrated openings 90 and the openings 84 in the nozzles 19, and, finally, through the borings85 is delivered into the zone 18 (FIG. 1) disposed behind the pipes of the hole 9, thereby effecting dust-suppression in the zone 18 in case the face 17 of the hole 9 is dry.

As the hole 9 becomesdeeper, the rods 8 of the drilling stem 7 are extended by any conventional technique.

The annular tank 25 (FIG. 2) is' charged with lubricant grease in the following way.

The spring ring 134 is extracted from the annular boring 135 (FIG. 4) of the opening 136 of the coupling 34, and the plug 131 is screwed out with the aid of a wrench inserted into the dead opening 133, then, the charging pipe union of the device used for charging the tank 25 with lubricant grease, which may be of any appropriate design (not shown in thedrawing is inserted into the central through opening 129 of-the nut 127. The charging pipe union presses the slide valve 121 to the right, compresses the spring and overlaps the passage 122, thereby closing the access for the lubricant grease to the bearings 26, 27 and 28 (FIG. 6) of the supports 29 of the rolling cutter bit 6. Concurrently, the slide valve 121 (FIG. 4) opens the passage 123 communicated with the tank 25 (FIG. 2) containing lubricant grease. Thereafter, the lubricant grease coming out of the charging pipeunion starts filling the tank 25 (FIG. 2) through the passage 123 (FIG. 4), while the drilling fluid to be found in the tank 25 under the scraping piston 265 is drained under the action of the pressure of the lubricant, transmitted via the scraping piston 265, through the means 111 specially provided for the purpose. At the same time, the drilling fluid is supplied via the passage 118 in the adapter 32,

the outer cut 264 (FIG. 7), the radial passage 262, the internal space 249, the radial passage 261, the outer cut 263 of the sleeve 235, the passage 194 into the cylindrical space 203 of the adapter 32, from which it passes inside the body 110 of the means 111 used for draining the drilling fluid, acts upon the valve 196 of the means 111 and by, overcoming the force of the spring 199, presses the valve 196 to the left, passes through the taper seat 195 of the body 110, and gets into the atmosphere through the central opening 207 in the nut 205. With the charging of the tank (FIG. 2) with lubricant grease completed, the spring 199 (FIG. 7) presses the taper portion 198 of the locking member 197 of the valve 196 against the taper seat 195 of the body 110, thereby overlapping the passage of the drilling fluid into the atmosphere. Thereafter, the charging pipe union of the device for charging the tank 25 with lubricant fluid is withdrawn from the central through opening 129 (FIG. 4) of the nut 127, as a result of which the spring 120 moves the slide valve 121 to the left to open the passage 122, thereby making it possible for the lubricant grease to get to the bearings 26, 27 and 28 (FIG. 6) of the supports 29 of the rolling cutter bit 6. Then, the plug 131 (FIG. 4) is screwed-in and is fixed in this position by means of the spring ring 134. Now the drilling stem 1 is ready for operation again.

When drilling rock which is likely to form packings, for example, rock containing clay interlayers, or when carrying-out drilling in ever-frozen ground, it is not desirable to supply drilling fluid into the hole. In this case the drilling machine (FIG. 1) may be equipped with a unit for dry dust catching or a unit using the principle of dust-suppression on the surface (not shown in the drawings), and pressurized air produced by a compressor (not shown in the drawing) which is mounted on the machine and is of a low efficiency and high pressure (exceeding the pressure of the main compressor 13) should be used for transmitting pressure to the lubricant grease instead of the drilling fluid. In this case the dust-suppressing nozzles 19 (FIGS. 1, 2 and 3) should be screwed out of the main pipe 33 and substituted with cap nuts (not shown in the drawing), this covering all the changes that are to be made in the design of the drilling stem. The diagram of movement of pressurized air from this compressor of a low efflciency What we claim is:

1. A drilling stem for drilling holes blown-out with pressurized air, comprising a rolling cutter bit; a pipe string connected to said rolling cutter bit; dustsuppressing nozzles disposedabove said rolling cutter bit; said pipe string having a passage for pressurized air and a passage for drilling fluid supplied under pressure to said dust-suppressing nozzles, said latter passage being separated from said former passage; a tank holding lubricant grease undergoing the pressure of the drilling fluid delivered from said separated passage, said tank being disposed above said rolling cutter bit; means for charging said tank with lubricant grease and for draining the drilling fluid from the tank while the latter is being charged; bearings of the supports of said rolling cutter bit; passages for delivering the lubricant grease from said tank to said bearings of the-supports of the rolling cutter bit. I

2. A drilling stem as claimed in claim I, wherein said means, for charging said tank with lubricant grease is made as a spring-loaded slide valve disposed under the tank, overlapping said passages in the course of charging, which communicate said tank with said bearings of the supports of the rolling cutter bit, and opening a passage connected with said tank.

3. A drilling stem as claimed in claim l, wherein said means used for draining drilling fluid from" said tank is made as a non-return valve positioned above said tank and communicated by a passage with its upper portion.

4. A drilling stem as claimed in claim 1, wherein said separated passage accomodates two passages mounted therein, of which valves one is connected by a passage with said dust-suppressing nozzles and opens an access thereto for the drilling fluid supplied under pressure, and the other one is connected by a passage with said tank containing lubricant grease, into which it opens an access for the drilling fluid, the former valve being adjusted for a higher pressure than the latter one.

5. A drilling stem as claimed in claim 1, wherein said tank accommodates a scraping piston which separates the lubricant grease from the drilling fluid, and moves as the level of the lubricant grease in the tank changes.

6. A drilling stem as claimed in claim 1, wherein at the point of disposition of said tank the lower rod of said pipe string is composed of three coaxial pipes of said dust-suppressing nozzles.

l =6 it t t UNITED STATES PATENT oFFICE CERTIFICATE OF CORRECTION Patent No. 3,749,186 Dated Julv 51L 1973 ,lniventofls) Boris Nikolaevich Kutuzov et a1 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Delete columns 3" and 4 and substitute in lieu thereof-- Fig. shows a rolling cutter bit connected with the lower I rod of the pipe string of the drilling stem, a longitudinal section; Q

Fig. 7 shows a valve mounted in the separated passage for the drilling fluid and opening access for the drilling fluid into the tank with lubricant grease and a nonreturn valve used for draining the drilling fluid from the tank while the latter is being charged with the grease (unit "D" in Fig. 2) a longitudinal section ;.l v

Fig. 8 shows a valve mounted in. the separated passage for the drilling fluid and opening access for the latter to the dustsuppressing nozzles (unit "C" in Fig. 2) a longitudinal sectiono The drilling machine shown in Fig: l is designed for drilling holes blown-out with pressurized air in quarries by rolling cutter bits and comprises a drilling stem 1 used as the working body and U5 C- HERNNENT PRAWNG GF ICE 5'3, c

Patent NO- The drilling machine also comprises a caterpiller undercarriage 2 and is mounted on a carrying frame 3. The drilling machine is set into its operating position for drilling holes with the aid of'horizontal hydraulic jacks 4', The drilling stem 1 is kept in its operating position, by means of a mast, and comprises a rolling cutter bit 6 connected with a pipe string 7 consisting of several rods 8 (8a, 8b 8n) which are added as the depth of a hole 9 increases.

The axial load acting on the "rolling cutter bit 6 is provided by means of a feeding device 10 ofany appropriate design, acting upon the pipe string 7, whereas the torque is transmitted to the m 11 via a resilient rolling cutter bit 6' from a rotating mechani coupling 12 and the pipe string 7.

The hole 9 is cleaned of particles of destruction products by pressurized air supplied from a compressor 13 along a hose 14 through a swivel l5 and a passage 16 (Fig. 2 made in the pipe string 7 to a face 17 of the hole 9 Figs. 2-5 and 7-8 show parts of the drilling stem, mounted in. the lower rod 8a of pipe string 7, and Fig. 6 shows the rolling cutter bit connected with the rod.

In order to decrease dusting of the air in the zone of the drilling machine provision is made for supply of pressurized drilling fluid, such as water, into a zone 18 of the hole 9 disposed behind the pipes through dust-suppressing" nozzles 19 (Figs. 1, 2 and 3) disposed above the bit 6 in the lower rod 8a of the pipe string 7. The drilling fluid is supplied to the dustsuppressing nozzles 19 by a pumping unit 20 of a controlled output of the pipe string 7 attributes to intensification of the process Patent No 3,749,186 Page 3 from a tank 21 via a pipe-line 22 a hose 23, a swivel and a passage. 24 (Fig. 2-) provided in the pipe string 7 and separated from the passage 16 I for pressurized air.

with the drilling fluid supplied into the zone 1 of the hole 9 disposed behind the pipes and above the bit 6 the drilling fluid is carried away by the upstream of the mixture of the I pressurized air and particles of destruction products and wettens said particles as a result of which they are coagulated into greater ones. Thereby, fine particles of destruction products that are most harmful for the man's health, deposit on large ones and, after being brought out of the hole, remain on the benching bank and do not pollute the atmosphere of the quarry. The rotation of coagulation of the particles of destruction products.

In addition to the, effective dust-suppressing} the supply of the drilling fluid into the zone l8 of the hole 9 disposed behind the pipes and above the bit 6 results in that the face 17 of the hole 9 remains dry ,7 which, as compared to dust-suppressing by way of su plying drilling fluid in the general flow of the pressurized air, substantially improves the operating conditions of the rolling cutter bit 6. In this case the speed of drilling and the endurance of the rolling cutter bits increase and approach the level attained in the case of drilling accompanied with methods of dry dustcatching which at present are being substituted with wet dustsuppressing techniques owing to impossibility of satisfying the sanitary norms of dusting of quarries atmosphere by using dry dustcatching'methods.

Patent No. 3,749,186 Page 4 M I 8 of Disposed above the rolling cutter bit 6 in the lower rod a the pipe-string 7 is a chamber or tank 25 (Pig. 2) d ted t c ntam v e n 2 I an I o I) .v l l.

cutter supports 29.

The lubricant greasing of the bearing 26 27 and 28 of the supports 29 of the rolling cutter bit 6 makes it possible to substantially increase the endurance of the rolling cutter bit 6 and to intensify the rates of drilling (to increase the axial load acting on the rolling cutter bit 6 and the rate of its rotation) owing to provision of favourable conditions of the operation of these bearings and, consequently, their higher operabi-lity.

The lower rod 8a (Fig. 2) of the drilling stein 1 comprises a nipple 30 having a taper thread 31 to be connected to a subsequent rod 8b (Fig. l) an adapter 32 a main pipe. 33 and a coupling 34 having an internal tape-r thread 35 to be connected to the rolling cutter bit 6. The adapter 32 has an upper taper thread 36 to be connected to the nipple 30 and a lower taper thread 37 to be connected to the main pipe 33 coupled with the coupling 34 by means of a taper thr ad 38 The passage 16 for pressurized air and the passage 24 for the drilling fluid, separated from the former, may be confined within the pipe string 7 by any appropriate way. In 2', for example the passages 16 and 24 are disposed coaxially with respect to each other.

Patent No. 3,749,186 Page 5 In the nipple 30 the passage 16 6? the pressurized air and the passage 24 for the drilling flu-id, separated from the former, are formed owing to employment of a sleeve 39 used to pack the space between the rods 8a, 8b and a sleeve 40 which is rigidly connected with the upper portion of the adapter 32.

The sleeve 40 has a thread join-t 41 with a sleeve 42 which in its turn, is rigidly secured by lneans of a weld joint 43 inside th upper portion of the adapter 32. In order to ensure a hermetic I sealing of the thread joint 41, a packing 44 is provided between the sleeve 40 and the sleeve 42. The upper portion of the sleeve 40 has a thickened head 45 by means of which it is centered relativ to the internal wall. 46 of the nipple 30. The head 45 of the sleeve 40 is provided with longitudinal. slots 47 allowing the drilling fluid to pass through. 

1. A drilling stem for drilling holes blown-out with pressurized air, comprising a rolling cutter bit; a pipe string connected to said rolling cutter bit; dust-suppressing nozzles disposed above said rolling cutter bit; said pipe string having a passage for pressurized air and a passage for drilling fluid supplied under pressure to said dust-suppressing nozzles, said latter passage being separated from said former passage; a tank holding lubricant grease undergoing the pressure of the drilling fluid delivered from said separated passage, said tank being disposed above said rolling cutter bit; means for charging said tank with lubricant grease and for draining the drilling fluid from the tank while the latter is being charged; bearings of the supports of said rolling cutter bit; passages for delivering the lubricant grease from said tank to said bearings of the supports of the rolling cutter bit.
 2. A drilling stem as claimed in claim 1, wherein said means, for charging said tank with lubricant grease is made as a spring-loaded slide valve disposed under the tank, overlapping said passages in the course of charging, which communicate said tank with said bearings of the supports of the rolling cutter bit, and opening a passage connected with said tank.
 3. A drilling stem as claimed in claim 1, wherein said means used for draining drilling fluid from said tank is made as a non-return valve positioned above said tank and communicated by a passage with its upper portion.
 4. A drilling stem as claimed in claim 1, wherein said separated passage accomodates two passages mounted therein, of which valves one iS connected by a passage with said dust-suppressing nozzles and opens an access thereto for the drilling fluid supplied under pressure, and the other one is connected by a passage with said tank containing lubricant grease, into which it opens an access for the drilling fluid, the former valve being adjusted for a higher pressure than the latter one.
 5. A drilling stem as claimed in claim 1, wherein said tank accommodates a scraping piston which separates the lubricant grease from the drilling fluid, and moves as the level of the lubricant grease in the tank changes.
 6. A drilling stem as claimed in claim 1, wherein at the point of disposition of said tank the lower rod of said pipe string is composed of three coaxial pipes of which the central one forms said passage for pressurized air, the central and inner one confine said tank containing lubricant grease, and the inner and outer ones confine said passage for drilling fluid supplied to said dust-suppressing nozzles. 